Frame members which are to be mitered can include doorframe members, window frame members and the like composed of steel, aluminum and even synthetic resin materials. These members may be fabricated from raw material in the form of a "profile", i.e. a length of the material which is of uniform cross section and which may comprise one or more webs and flanges angularly adjoining one another and at least one of which can form a trim flange.
When the profile is formed from aluminum or synthetic resin material, it is generally extruded, and when it is formed from steel, it is generally formed by rolling.
The ends of each length are originally perpendicular to the longitudinal edges of the profile and for assembling a frame from members cut to length from the profiles, it is necessary to miter these lengths, i.e. cut the ends thereof at a bias to the longitudinal edges, generally at an angle of 45.degree..
The mitering of frame profiles to size has generally been carried out by a sawing operation heretofore. This is disadvantageous for various reasons. For example, it forms burrs and especially sharp edges which along the trim flange lead to a poor finish of the frame.
At least in part this may be because the sharp trim edges do not always meet with precision during the mounting of the frame even when the frame members form part of a prefabricated frame structure adapted to be inserted in a door buck or frame opening. Some leeway must generally be provided to accommodate the frame to the frame opening and hence even where the frame members are connected together for use with prehung doors, some mobility may be required.
Furthermore, the sharp edges may introduce handling problems especially at the trim edge or flange.
Accordingly, these earlier systems resulted in time consuming and expensive deburring and finishing operations even where the trim edge was to be welded to the trim edge of an adjoining profile in a prehung door arrangement.
Furthermore, the sawing operation is time consuming because the saw cutting of a workpiece is comparatively slow, and gives rise to saw wear requiring frequent replacement or sharpening of the tool.
It has also been proposed to miter frame members from such profiles by a stamping or punching operation. While this eliminates the tool wear and burr problems previously mentioned, the desired rounded contour of the trim edge cannot be obtained by these earlier stamping operations and, indeed, problems may be encountered in the deformation of the profile between long-cut regions at which two frame members are to adjoin in mirror-symmetrical relationship and the trim edge.